Swamp Sparrows are winter birds in Massachusetts: the first arrive in late March, they are common by the second week of April, peak in the second week of October (19% of checklists), and most are gone by late November.
When to look
First arrivalsMar 22-31late March
Common byApr 8-14the second week of April
PeakOct 8-14the second week of October
Most gone byNov 22-30late November
Best: the second week of October. First arrivals late March; most are gone by late November. Peak: on about 19% of Massachusetts checklists.
Januncommon
Febrare
Marrare
Aprcommon
Maycommon
Juncommon
Juluncommon
Auguncommon
Sepcommon
Octpeak season
Novcommon
Decuncommon
Darker months: more checklists report it. Outlined: peak month.
Share of complete checklists reporting it, by week (4 per month). Grey bars: fewer than 10 checklists, not counted.
Frequency is the share of complete checklists in Massachusetts that listed the bird, 2016–2025. It is not a head count, and it follows where and when people go birding. How to read it.
JanFebMarAprMayJunJulAugSepOctNovDec
today
0%few checklistsno data
Each county is shaded by the share of complete checklists there that listed the bird, blended with the weeks either side. Darker is more often. It follows where people watch birds, not how many birds there are. How to read it.
Post FarmBerkshire County, best mid June · 29 checklists that week, 733 in all89%
Parsons Marsh ReserveBerkshire County, best mid June · 23 checklists that week, 726 in all88%
Busy spots report more of everything; compare the checklist counts before you drive anywhere.
Best time of day
In Massachusetts, the Swamp Sparrow is most often listed on checklists started between 6 and 8 am (11% of those checklists).
Share of checklists started in each local hour that reported it. It reflects when people go birding as well as when birds are active. Grey hours have too few checklists (under 2% of the state’s, or under 200) to judge.Week-by-week table
Month
Days 1-7
8-14
15-21
22-end
January
2.7%
2.3%
2.2%
2.4%
February
2.3%
2.1%
1.5%
1.6%
March
1.4%
1.3%
1.5%
2.2%
April
3.7%
7.5%
11%
12%
May
12%
10%
9.1%
7.8%
June
7.4%
7.8%
7.4%
7.3%
July
7.4%
7.2%
7.2%
6.8%
August
4.8%
3.6%
2.6%
2.7%
September
2.6%
3.8%
6.2%
11%
October
18%
19%
19%
16%
November
9.5%
7.2%
6.0%
4.8%
December
4.2%
3.9%
4.8%
4.4%
Neighboring states
Rhode Island: arrives the second week of September, 22 weeks later than Massachusetts
New Hampshire: arrives early April, 1 week later than Massachusetts
Connecticut: arrives mid March, 1 week earlier than Massachusetts
Vermont: arrives early April, 1 week later than Massachusetts
Common questions
When do Swamp Sparrows arrive in Massachusetts?
Swamp Sparrows are winter birds in Massachusetts: the first arrive in late March, they are common by the second week of April, peak in the second week of October (19% of checklists), and most are gone by late November.
When do Swamp Sparrows leave Massachusetts?
Most Swamp Sparrows have left Massachusetts by late November, when reports fall below half their usual rate. Stragglers are still reported until early February.
When is the best time to see a Swamp Sparrow in Massachusetts?
The Swamp Sparrow is reported most often in the second week of October, on about 19% of Massachusetts checklists.
Where in Massachusetts are Swamp Sparrows seen most often?
By county, Worcester County, Middlesex County, and Bristol County have the highest peak reporting rates for the Swamp Sparrow (counties with at least 200 checklists).